This blog chronicles the research of the UsefulChem project in the Bradley lab at Drexel University. The main project currently involves the synthesis of novel anti-malarial compounds. The work is done under Open Notebook Science conditions with the actual detailed lab notebook located at usefulchem.wikispaces.com. More general comments posted here relate to Open Science, especially when associated with chemistry.

Wednesday, July 29, 2009

Iterating a 5D solubility space

About three weeks ago I described how we are mapping a 5D solubility space (mixtures of 4 solvents and temperature). Andrew Lang has been re-running his code to populate the DoSol request sheet with the most useful next measurements. After a few iterations of Marshall Moritz doing experiments and combining with any existing data from the literature we now have 76 measurements for the solubility of 4-nitrobenzaldehyde in mixtures of chloroform, acetonitrile, toluene and THF within the temperature range of -25 to 40 C.

We are now working on ways of quantifying how well we have covered the space and how confident we are of specific predictions. At some point we would like to generalize the predictions based on molecular descriptors of the solvents.

The existing dataset can be sliced in some interesting ways. For example, using Mathematica, Andy has created a plot of the solvent combinations giving the highest possible solubilities of 4-nitrobenzaldehyde at a given temperature. At room temperature this corresponds to a mixture of 38% chloroform and 62% acetonitrile (molar ratio). Below 10C, toluene enters the mix to obtain maximum solubility. At no temperature does THF help.